1. Field
The present invention relates to a diffuser-integrated prism sheet for backlight units and a method of manufacturing the same. More particularly, the present invention relates to a prism sheet for backlight units, in which diffuser layers are provided on upper and lower surfaces of the prism sheet and prism-shaped protrusions are formed in the prism sheet, and to a method of manufacturing the same.
2. Description of the Related Art
FIG. 1 illustrates the construction of a conventional backlight unit.
As illustrated in FIG. 1, in the conventional backlight unit, a fluorescent lamp 1, which is a linear light source, and a lamp reflector plate 2 for reflecting the light of the fluorescent lamp 1 are disposed to one side of a light guide plate 3 for using the light from the fluorescent lamp 1 as a surface light source, and a reflector sheet 4 for preventing the leakage of light is disposed under the light guide plate 3. Further, a diffuser sheet 5 for uniformly diffusing light is placed on the light guide plate 3, and prism sheets 6, 7 respectively having a plurality of triangular linear prisms 8, 9 to collect scattered light are sequentially placed on the diffuser sheet 5. Two prism sheets 6, 7 are disposed so that linear prisms 8, 9 are perpendicular to each other, thus collecting light radiated in different directions. On the upper prism sheet 9, a protector sheet 10 for protecting the prisms from being scratched and preventing the entry of impurities between the prisms is disposed. The individual constituents are assembled, thereby completing a backlight unit.
However, because the conventional prism sheet has the prism-shaped protrusions on one surface thereof, defects caused by scratching of the prism-shaped protrusions and by the entry of small impurities into the valleys between the prism-shaped protrusions and shatter cracks caused by cutting of the prism-shaped protrusions, attributable to friction with the protective sheet, may be generated when the backlight unit is assembled. Hence, even if the backlight unit is carefully assembled, many assembly defects may occur, undesirably decreasing productivity, and furthermore, in the case where defects occur, the manufacturing process must be conducted again, resulting in high material cost loss.
Further, problems occur because the diffuser sheet, the prism sheet, and the protector sheet must be sequentially and separately layered in the assembly process.